Valve-gear



(No Model.) I 2 Sheets-Sheet 1.

F. S. MOKIBBEN. VALVE GEAR.

No. 438,085. Patented Oct. 7, 1890.

(No Modem I 2 Sheets-Sheet 2,

P. MGKIBBEN.

VALVE GEAR.

.No. 488,085. Patented Oct. 7, 1890.

- JMJQ/ &

FRANK S. MCKIBBEN, OF JOSEPH, OREGON.

VALVE- GEAR.

SPECIFIGATION forming part of Letters Patent No. 438,085, dated October 7, 1890.

' Application filed November 25,1889. Serial 110.331.5235. camel.)

To all whom it may concern:

Be it known that I, FRANK S. MOKIBBEN, a citizen of theUnited States, residingat Joseph, in the county of WVallowa and State of Oregon, have invented certain new and useful Improvements in Valve-Gears, of which the following is a specification.

The object is to provide a distributing-valve for steam-engines, combined with a cut-off or expansion valve, both being balanced and held to slide nearer the entrance to the cylinder than usual, so as to save most of the steam ordinarily required to fill the passage between the steam-chest and cylinder, and to provide an actuating-gear suited to the peculiarities of the valves, to be controlled by the governor of a stationary engine and by the engineer of a locomotive, so as to out ofi steam at any desired time in the stroke, while the exhaust is allowed to escape freely during the whole stroke.

In the annexed illustrative drawings, Figurel is a side elevation partlyin section. Fig. 2 is an end elevation. Fig. 3 is a plan view of the actuating-gear. Fig. 4 is a section on the line 00, Fig. 5 a section on the line y, and Fig. 6 a section on the line .2, Fig. 1. Fig. 7 is the cut-off link detached. Fig. 8 represents a well-known combination of a distributing and a cut-oft valve. Fig. 9 is a diagram representing the position of the eccentrics.

In order that the valves may be as near as possible to the cylinder, the steam-chest occu-' pics the middle portion and the exhaust es: capes into a receiver, which projectsover the ends of the cylinder and may form a jacket over the steam-chest, as in Fig. 1.

The plate 1, forming the cover of the steamchest, is movable, andis held against the top of the main valve by screws 2 or any other suitable means with sufficient firmness to resist the pressure of steam from below and prevent leakage and still allow the valve to move freely. .The action of this plate and its false ports in balancing the valve will be suf-' ficiently understood without an extended explanation. A small steam-chest and exhaustreceiver may be placed at each end upon the same plan. The steam and exhaust chambers may be also made much shorter than repre sented in Fig. 1, so as to occupy no more space than the ordinary steam-chest, the passages to the cylinder being the usual length.

The valves are each in two parts-one part at each endand suitably connected by one or more rods. The valves thus form the ends, while the plate 1 forms the top, of the steamchest. Each part of the distributing-valve consists of a body 3, nearly lozenge-shaped in section, and a wing 4, with a steam-port between them. The upper and lower faces of the body are sufficient to cover the false and true ports, a small lap, ornone at all, being preferred. In each side may be placed a packing-plate 5, Figs.4 and 6, (and a spring) facing against the. side of the steam-chest. Within the side ribs of thevalve are passages 6, Figs. 1, 5,'and,6, throughwhich the upper and lower portions of the, valve -port communicate, so that thepressure above and beloW may be equalized, While the cut-01f valve closesthe port. Each section of the cut-01f valve is a simple plate 7, held to slide through the main or distributing valve.

The eccentrics or other means for giving motion to the main valve must be so placed that the valve may move oppositely to the piston in the first half of the stroke to accord with the relative position of steam and exhaust. Otherwise the main valve receives its motion through parts very similar to those in common use.

. To actuate the cut-off valve, itis connected by a rod 9 to a block sliding ina link 10, Fig. 7, which is slotted in about three-fourths or more of its length and pivotedby the center of its upper unslotted end between the upper ends of two parallel levers or arms 11,- fixed upon a shaft 12, journaled in a bracket 13. The link is pivoted by the center of one end, so that it will not have so much upward and downward motion as whenpivoted at one side. In the bracket 13 another rock-shaft 14: is journaled, having two arms extending downward and parallel to each other. The short arm 15 is connected by alink 1 6 to the lower end of the slot-link, and the longer-arm 17 is connected to a bracket 19, secured to the piston cross-head. The length of these'arms should be so proportioned that the lower end of the slot-link will have amovement about equal to that of the main valve whenin full gear.

The shaft 12 may entirely take the place of 5 the ordinary rock-shaft as used on locomotives by being connected to the reversinggear, as represented in Figs. 1 and 2.

In stationary engines, whether reversible or not, the eccentric-rod or its equivalent may usually be pivoted to the arms l1,as indicated by the line A, Fig. 1.

The main-valve rod 24 is double, and its two parts are pivoted, respectively, to the 7 parallel arms 11 of the rock-shaft 12 below I 5 their centers. The main-valve rod and the arm may be made single, if desired.

The position of the link-block is to be regulated by a governor in most stationary engines; but in locomotives it is shifted by means of a shaft 22, extending from one side to the other of the locomotive and having arms 23 to act much the same as a bell-crank lever.

A guideway (not represented) for the stem 8 of the cut-off valve may be secured to the end of the steam-chest.

In the operation of this valve-gear the connections and movements of the main valve need be changed only to reverse the engine. This, together with the small amount of lap, renders it unnecessary or impossible to produce compression in order to obtain an early cut-off, which always occasions some loss of power, not compensated for when the common single valve is used.

At the beginning of the piston-stroke the main valve and the arms 11 are in their central position, as represented in Fig. 1. The upper end of the cut-01f slot-link is therefore in the center, while the lower end is forward or backward, according to the position of the piston. When the link-block is in the upper end of the slot, the cut-01f valve is influenced slightly by the movements of the lower end of the link, and is carried past its central position, so as to open the valve-port a little be- ,fore the cylinder -port is opened. As the movement continues the valve-port is opened as fast as the cylinder-port is, because the cut-off valve is actuated more by the upper end than by the lower end of the link, and that by its connection with the arms 11 moves faster than the main-valve connection with the same arms. As the valves return in the last half of the piston-stroke the cut-off valve, now carried in the same direction by both ends of the link, overtakes the main valve and cuts off slightly before the end of the stroke. If the block is shifted to the lower end of the link, then at the beginning of the stroke the cut-ofi valve is at its farthest point in the same direction as the piston. As the movement of the main valve is opposite to that of the piston in the first half of the stroke, the cut-off valve, moving with the piston, cuts off steam very early in the stroke. Thus in the first half of the stroke the cut-off is accomplished by the cut-off valve meeting the main valve, while in the last half of the stroke the cut-off is accomplished by the cut-ofi valve overtaking the main valve. The ports are open almost to their full width some time in each stroke, even for the earliest cut-0E.

Fig. 8 represents-a common form of combined valves which may be actuated advantageously by the gear here described if the eccentrics are placed in the usual position so that the main valve and piston will move in the same direct-ion in the first part of the stroke. In this case, however, the early outoff occurs when the cut-off valve, being in gear with the upper part of the slot-link, overtakes the main valve,.and the late cut-01f occurs when the cut-off valve, being in gear with the lower end of the slot-link, meets the main valve; also, the cut-off is eifected by the cut-off "alve coming in contact with the body of the main valve instead of with the wing. The edges of the expansion-valve by which the cut-off is eifected are farther apart than the cut-off edges of the main valve, while in the combination that is represented in Fig. 1 the cut-off edges of the expansion-valve are about the same distance from each other as are the cut-off edges of the main valve. With a main valve having no lap and a travel equal to two and a half or three times the width of the port, the travel of the expansionvalve when in gear with the lower end of the slot-link being also two and a half or three times the width of the port, then good results will be obtained if the cut-off edges of the expansion-valve are as far apart as the cutoff edges of the main valve plus three-fourths of the width of the port. These measurements may be varied within certain limits.

In Fig. 9 are shown the relative positions of the crank and eccentrics and the points at which the cut-0E occurs. The diagram is intended for a main valve having no lap inside or outside. Hence the eccentrics are at right angles from the crank. The earliest and latest c'ut-ofis may be made to occur earlier in the stroke (but the same distance apart) by using an expansion-valve whose cut-off edges are relatively nearer to each other. If the combination represented in Fig. 8 is used, the main eccentric'becomes the backlng-ecoentrio. The range between the earliest and latest cut-offs is about the same; but both will occur earlier than represented in the diagram.

Having described my invention,I claim as new and desire to secure by Letters Patent as follows:

1. In a valve gear, a distributing slide valve in two distinct parts, one at each end of the cylinder, and an expansion-valve, also in two parts, each being a simple fiat plate held to slide in the corresponding part of the main valve and a simple flat balancing-plate having false ports in its under surface, when they are formed substantially as described and combined so as to form the ends and top of the steam-chest proper and so as at the same time to make both valves balanced.

2. In a valve-gear in which an expansionvalve is actuated independently of the distributing-valve, a link 10, for actuating the expansion-valve, which is slotted only in a portion of its length, pivoted by the center of its upper unslotted end to an actuating arm or lever 11, and connected at the side of its lower end by a lever and connecting-rods, so as to receive motion from the piston.

3. In a valve-gear, a link 10, for actuating an expansion-valve independently of the distributing-valve, slotted in only a portion of its length, and pivoted at the unslotted end to an actuating arm or lever and connected to the piston at the other end, in combination with a sliding block and rod 9, connecting said link to the expansion-valve, and a shaft 22, with arms 23, connected to the said valverod, for shifting the block in said link.

4. In a valve-gear, a rook-shaft 12, having arms 11 fixed thereon, to the central portion of which the main-valve rod 24 is pivoted and to the extremity of Which the upper end of a cut-0E link 10 is pivoted, the other end of said link receiving motion from the piston through a lever and connecting-rods.

5. In a valve-gear, a rock-shaft 14, having a short and a long arm 15 and 17 extending in the same direction and fixed thereon, the former being connected by a link 16 to the lower part of the slot-link and the latter being connected by a link 18 to a bracket 19, fixed upon the cross-head of the piston.

FRANK S. MOKIBBEN.

Witnesses:

T. J. DEAN, A. W. GOWAN. 

